Basic Terminology Of A Circle:

Before moving on to find the area of a circle, this page covers the basics about a circle. First of all kids need to know, what a circle is and why they need to study about it? Below is a try to clear all the questions about a circle;

Definition Of A Circle

Mathematically, a circle is a locus (or path) of all the points, whose distance from a fixed point remains fixed.

Many students take this definition as very cumbersome. Let’s simplify the above words by taking an example of a cow tied to a pole with a rope and moving around the pole. What do you think the shape of the path will be?

Now the word “locus of all the points” is cow’s path and the this path is always at a fixed distance (the length of the rope) from a fixed point which is the central pole.

Hope above example have cleared some confusion about the definition of the circle.

In daily life we can see many examples of circles; engagement ring is a very good example of a circle, the other examples may include, bangles, donuts and the caps or lids of many containers.

After knowing the definition of the circle, the next step is to find circumference and area of a circle.

To do these tasks we need to define some basic terms about a circle. There are the following basic terms associated with this geometric shape:

Center: The fixed point at the center of the shape is called the center of the circle. In our example of cow, the central pole represent the center.

Radius: The fixed distance from center to path is known as the radius of the circle. In cow example, the length of rope represent the radius.

Diameter: The length of a line across through the center is called the diameter. In other words, diameter is twice as long as the radius. Or 2 times radius length gives the length of the diameter.

Circumference: The total length of the circular path is known as the circumference. For example; if we want to fence the path of the cow then the length of the fence will be circumference.

Area of the circle: Plane surface enclosed inside the circumference is known as the area of the circle. For example; the grass inside the path covers the area of the circle formed by cow’s movement.

It is highly recommended for students to take a note of all the above basic terms related to a circle. These are very useful terms to learn higher concepts about circles, such as finding area and circumference of a circle, application of circles in geometry.